1. Field of the Invention
The present invention relates to a power source for a printer such as a thermal printer.
2. Description of the Related Art
A circuit structure in a general power source for a printer is provided to detect a power voltage or a voltage drop in a thermal head portion of the printer. In this case, it is necessary to locate a remote sensing line between a circuit for detecting the voltage drop and the power source or the thermal head portion. When a defect in a remote sensing connector is caused in the thermal head portion, a thermal voltage is excessively increased. Therefore, it is necessary to separately locate a circuit for protecting the thermal head portion from the excessive voltage.
In the above-mentioned general power source, an output voltage of the power source is reduced in accordance with an increase in printing amount so that a difference in density between printed characters is caused.